Circuit breaker



June 15, 1954 v B. B. scHwAR-rz ET AL 2,681,397

CIRCUIT BREAKER Filed Jan. 2, 1953 2 Sheets-Sheet l INVENTORS.

June 15, 1954 B B, SCHWARTZ ET Ax. 2,681,397

CIRCUIT BREAKER 2 Sheets-Sheet 2 Filed Jan. 2, 1955 INVENTURS KSCwa/*Z Patented June 15, 1954 UNITED STATES PATENT OFFICE CIRCUIT BREAKER Application January 2, 1953, Serial No. 329,222

9 Claims.

This application relates to circuit breakers and discloses an improvement in the circuit breaker disclosed in prior Patents 2,374,778, issued May 1, 1945, to E. T. Platz; 2,385,727, issued Septemberl 25, 1945, to E. T. Platz; 2,487,725, issued November 8, 1949, to E. 'I'. Platz; and 2,563,103, issued August 7, 1951, to R. S. Davis.

These` patents disclose a circuit breaker having a push button type operation which may be manually operable successively for opening and closing the breaker contacts. The breaker is automatically operable for opening the breaker contacts upon the'occurrence of an overload in the load circuit containing the breaker.

Previously in the art of circuit breakers, various attempts havel been made to obtain a circuit breaker mechanism which provides quick-make and quick-break. These terms may be defined as follows: When the circuit breaker is in the on position; i. e., When the contacts thereof are engaged, and the opening or separation of the contacts is eiected', by either manual or automatic operation, and this separation is effected by the circuit breaker mechanism by a rapid movement of one contact away from the other, independently of the initiating agency, then this rapid separation is known as quick break; similarly when the circuit breaker mechanism, once set into operation manually while in the off or contact separated condition, causes the contacts to mover together rapidly, independently of the'initiating agency, then this operational feature is known as quick make.

Many different beneficial results flow from these features, including` less heating of the contacts, less erosion of the contacts, both of which I result in longer contact life.

Asignicant disadvantage of circuit breakers of the prior art was the bouncing of the conta'cts upon quick make. This bouncing resulted ina multitude of progressively smaller arcs being drawn between the contacts, and therefore, accelerated contact erosion and heating,- even though the breaker provided a quick make mechanism.

The problem then presented was twofold: First, to provide a quick make mechanismyfor a circuit breaker; and secondly, to eliminate the usual bouncing disadvantage with its attendant contact wearing found in prior art quick make breaker constructions.

Therefore, a prime object of this invention is to provide a quick make mechanism for a circuit breaker.

Another object of the invention is to provide a quick make mechanism for a circuit breaker that is free of undesirable` bouncing of the contacts.

Another object is to provide a quick make breaker mechanism that is readily adaptable to an existing slowmake breaker.

A circuit breaker mechanism providing features that satisfy the above objects is illustrated in the accompanying drawings in which:

Fig. 1 is an elevational View of a circuit breaker in the oil (contact separated) position with the side removed showing the interior construction.

Fig. 2 is an elevational view of a composite contacter and bimetal latch.

Fig. 3 is an elevational View of the support plate.

Fig. i is an elevational view of a circuit breaker with the side removed showing the breaker mechanism in an intermediate position prior to quick make.

Fig. 5 is an elevational view of a circuit breaker with the side removed showing the breaker in the fully on position.`

Fig. 6 is a fragmentary view of an alternative embodiment of the composite member of Fig. 2.

Referring to the drawings, a circuit breaker as disclosed herein includes a casing l of a molded insulating material shown with one side removed (Figs. l, 4, 5). Extending through the rear wall of this casing is a line connector 25 having secured thereto a fixed Contact 26, and a load connector (not shown). Formed integral with the side and bottom, respectively, of casing l are extensions i 3 and 30 adapted to be engaged by the breaker mechanism as hereinafter described. Also formed in the rear wall of this casing are grooves (not shown) in which an operator, or a handle 2 is slideably disposed, which in conjunction with t-he front side of casing l serve to guide the handle in its inward and outward movement. Beneath the handle 2, With one end extending into a recess thereof is a handle return spring 3 the opposite end of which is seated on an abutment i projecting from the back side of casing l. Also, below the operating handle 2 and adjacent to the rear wall of the casing I (Figs. 1, 3, 4, 5) and arranged to be engaged by an extension 5 of the handle 2 when the breaker is in the on position is a support plate E (Fig. 3). Extension 5, upon inward movement of handle 2, contacts this support plate 6 in the notch l, preventing lateral movement of the support plate and im`n parting the operating force applied to the handle to the breaker mechanism. The support plate 6 vcasing I at 24 is a mainspring 23.

has cut-out portions 9, I0, Il, and I?. (Fig. 3). Cut-out portion 9 journals pivot pin I2 of the composite contactor and latch bimetal ill and cutout portion I6 provides clearance for lug i3 extending from side I4 of casing l. Cut-out portion II receives guide lug I6 which projects from the rear Wall of casing I. This lug I6 dennes the movement of support plate 6 upon operation of the breaker mechanism.

Extending from the upper portion of support plate 6 is a cam 26 which interacts with a cam surface 3S (Fig. 5) on handle 2 as disclosed in Patent 2,563,103 referred to supra to return support plate 6 positively to the open circuit position.

Cut-out portion I2 of support plate 6 defines a latch surface 3l (Fig. 3) arranged to be engaged by a latch hook I8 of the bimetal portion I'I of a composite member I when the mechanism is in the on position. This composite member i6 overlies the support plate 6 and is secured to it in a pivotal relationship by pivot pin I2. Conv posite member I5 is comprised of a bimetal Il having a latch hook I3, and an L-shaped contactor I9. Secured to one end of the lower leg :l5 of this contactor I6 is a moveable contact 2l. Formed integral with the upper leg i4 of the contactor I9 is a mainspring lug 42 and a lug 20. Having its upper end seated against mainspring lug 42 and its lower end seated in the This mainspring 23 biases composite member I5 counterclockwise about pivot pin l2 and also inward against support plate 6. The extent of the inward deflection or composite member l5, when the breaker mechanism is in the on circuit position, is controlled by a turned-down portion 46 of upper leg 46 of contacter I9. This turneddown portion 46 abuts the upper surface of sup port plate 6 and thus determines the overlap of latch hook I8 at latching surface 3l of support L member I5 when the breaker mechanism is in the on or closed circuit position.

Secured to the upper end of bimetal Il is a exible conductor 22 which connects the bimetal II with a load connector (not shown) which extends through the back of casing I.

The manual operation of the preferred embodiment is as follows: Upon manual depression of handle I when the breaker is in the oli or open circuit position (Fig. 1) i. e., with the contacts 26,

2| separated, extension 5 of operating handle 2 engages the support plate 6 in notch l'. Upon further inward movement of the operating hann dle 2 against the bias of spring 4, the support plate 6 moves downward with its movement restricted by the lost motion engagement oi the cut-out portion I I and guide lug I6. As the support plate moves downward under the force transmitted through operating handle 2, the composite member I5 having pivot pin I2 journaled in cut-out portion 9 of the support plate 6 also moves downward until the lower edge 29 of contactor arm I9 strikes projection 36 in the bottom of casing I. Further depressing of the handle 2 is transmitted to composite member I5 and converts this downward movement of composite member I5 to clockwise rotary movement around pivot pin I2 against the bias of mainspring 23. This results in composite member i5 moving clockwise until latch hook I8 of bimetal II clears latching surface SI (Fig. 3) of support plate 6. Mainspring 23 which exerts an upward as well as an inward bias on composite member I5 then forces latch hook I8 inward behind latching surface 3l, until the turned down portion 4 46 on the upper leg 44 of contactor I6 abuts the upper surface of support plate 6. Upon handle 2 being released, support plate 6 moves upwardly carrying composite member I5. After a short upward movement lug 20 of contacter I9 strikes extension I3 on the side of the case I. The breaker mechanism is then in the position shown in Fig. 4 with the contacts 2|, 26 spaced apart. Upon further release of handle 2, extension I3 of casing I retards further upward movement of composite member I5 and, therefore, of support plate 6 and also cams these elements to the left. Further upward movement of the handle, as upon its complete release by an operator, results in the disengagement of notch 'I of support plate 6 from the handle extension 5. At this release point the support plate 6 and composite member I5 move rapidly upward and to the leit under the iniluence of mainspring 23, but independently of the position or operation of handle 2, until contacts 2 I, 26 are engaged. The breaker is then in the on position as shown in Fig. 5.

If it is desired to open the breaker manually, handle 2 is again depressed. A cam surface 34 (Fig. 1) of the handle 2 strikes the undersurface of latch hook I8 of bimetal I'I, raising it upward until latching surface 3| of the support plate 6 is cleared, at which time the composite member l5 is rotated counterclcckwise about pivot I2 under the force of mainspring 23, separating contacts 25, 2i instantaneously. Automatic opening of the mechanism is accomplished by the release of bimetal Il due to warping under an electrical overload. The breaker then is in the fully off position of Fig. 1.

An alternative embodiment of the composite member is shown in Fig. 6. In this embodiment the projection 26 in the upper leg 44 of contactor I9 is deleted. To obtain the quick make action, a cam surface 52 is formed upon the end oi upper leg 44 of contactor I9. This cam surface 52 engages extension I3 of casing I, thus providing the retardation and cam action to disengage the breaker mechanism from the handle and permit the contacts to close instantaneously.

Having described the circuit breaker herein disclosed, reference should be had to the claims which follow for a determination of the invention.

We claim:

1. In a circuit breaker having a casing, a fixed contact, an operating member slideably disposed in said casing, a support plate actuable by said operating member, a composite member actuable by said support plate, the composite member including an electroresponsive latch element engageable and disengageable from said support plate upon successive operation of said operator and a moveable contact carrying element, said composite member and said casing comprising means whereby said nXed and said moveable contacts are caused to close instantaneously.

2. In a circuit breaker, a casing, a xed contact, an operating member slideably disposed in such casing, a support plate actuable by said operating member, a composite member actuable by said support plate including an electroresponsive latch element engageable and disengageable from said support plate upon successive opn eration of said operator and a moveable contact carrying element, said contact carrying element and said casing comprising means to cause said xed and moveable contacts to close instantaneously.

3. In a circuit breaker, a casing, a xed contact, an operating member, a support plate actuated by said operating member, a composite member including an electroresponsive latch member engageable and disengageable from said support plate upon successive operation of said operator, a contactor, and a moveable contact, said contactor having means which interacts With said casing to cause said iixed and moveable contacts to close instantaneously.

4. In a circuit breaker, a casing, a iixed contact, a mechanism including a resiliently biased operating member, a support plate actuable by said operating member, a composite member including an electroresponsive latch element, a contactor, and a moveable contact, a resilient element for moving said support plate and said composite member to open circuit position from closed circuit position upon operation of the operating member and to closed circuit position from open circuit positian upon a successive operation of the operating member, the casing and the composite member having interacting means to cause the mechanism to be released from the operating member to permit the nxed and moveable contacts to close instantaneously.

5. In a circuit breaker having a casing, a xed Contact, a mechanism, including a resiliently biased operating member, a support plate actuable by said operating member, a composite member including an electroresponsive latch element, a contactor, and a moveable contact, a resilient element for moving said support plate and said composite member to open circuit position from closed circuit position upon operation of the operating member and to closed circuit position from open circuit position upon a successive operation of the operating member, the casing and the composite member having interacting means to cause the support plate to be released from the operating member to permit the xed and moveable contacts to close instantaneously.

6. In a circuit breaker, a casing, a xed contact, a mechanism including a resiliently biased operating member, a support plate actuable by said operating member, a composite member including an electroresponsive latch element, a contactor, and a moveable contact, a resilient element for moving said support plate and said composite member to open circuit position from closed circuit position upon operation of the operating member and to closed circuit position from open circuit position upon a successive operation of the operating member, the composite member interacting with said casing whereby the mechanism is cammed free oi said operating member to permit the xed and moveable contacts to close instantaneously.

7. In a circuit breaker, a casing, a xed contact, a mechanism including a resiliently biased operating member, a support plate actuable by said operating member, a composite member inciuding an electroresponsive latch element, a contactor, and a moveable contact, a resilient element for moving said support plate and said composits member to open circuit position from closed circuit position upon operation of the operating member and to closed circuit position from open circuit position upon a successive operation of the operating member, the eontactor interacting r-:ith whereby the mechanism is cammed free of said operating member to permit the fixed and moveable contacts to close instantaneously.

8. In a circuit breaker, a casing, a xed contact, a mechanism including a resiliently biased operating member, a support plate actuable by said operating member, a composite member including an eleotroresponsive latch element, a contacter, and a moveable contact, a resilient element for moving said support plate and said composite member to open circuit position from closed circuit position upon operation of the operating member and to closed circuit position from open circuit position upon a successive operation of the operating member, the contactor having means thereon which interacts With said casing to cam the mechanism free oi said operating member to permit the xed and moveable contacts to close instantaneously.

9. In a circuit breaker, a casing, a xed contact, a mechanism including a resiliently biased operating member, a support plate actuable by said operating member, a composite member including an electroresponsive latch element, a contactor, and a moveable contact, a resilient element for moving said support plate and said composite member to open circuit position from closed circuit position upon operation of the operating member and to closed circuit position from open circuit position upon a successive operation of the operating member, the combination comprising cam means interconnecting said resilient element and said casing whereby said Xed and moveable contacts are caused to close instantaneously.

References Cited in the file Of this patent UNITED STATES PATENTS Number Name Date 2,132,627 Jackson Oct. 11, 1938 2,148,880 Sattler Feb. 28, 1939 2,409,917 Von Hoorn Oct. 22, 1946 

